Memory Stick in SD slot

[sinsi]

So I have a Sony Memory Stick which doesn't register, even in the camera it came with.
Now I know that things can die all by themselves, but is there a sinister explanation?
I assume that card readers get power via USB. Could plugging the stick into the SD slot short it out?
No reader I use (in a couple of PCs) trigger a disk mount, but the reader lights up the 'access' LED.

My thinking is: they killed it by plugging it into the wrong slot.

[dedndave]

static electricity - or a nice little voltage transition can do the job
i am surprised we don't hear more of this

[MichaelW]

Static electricity can be a real problem under low-humidity conditions. I’ve seen conditions where you could walk a short distance across carpet, then reach for a metal doorframe and hear the arc pop.

[WillASM]

Try plugging it back into your PC and see if it shows up under "Computer Management". If it does, try to format it from there.
If it does not show up, then you are most likely out of luck with that stick..

[CommonTater]

So I have a Sony Memory Stick which doesn't register, even in the camera it came with.
Now I know that things can die all by themselves, but is there a sinister explanation?
I assume that card readers get power via USB. Could plugging the stick into the SD slot short it out?
No reader I use (in a couple of PCs) trigger a disk mount, but the reader lights up the 'access' LED.

My thinking is: they killed it by plugging it into the wrong slot.

Plugging it into the wrong slot is more likley to short out the reader than the memory. 
Although, these things do happen from time to time.

As already suggested... see if it shows up under disk management.  If not... trash time.